1. Field of the Invention
The invention relates to a filter useful for separating liquid from solid particles. More particularly, the invention comprises a removable filter which comprises vertically arrayed and manifolded filter sections connected to a common filtrate collector, useful for separating liquid hydrocarbon product from a Fischer-Tropsch hydrocarbon synthesis slurry comprising catalyst particles in a hydrocarbon liquid, and to a hydrocarbon synthesis process employing same. Each filter section comprises a plurality of elongated, vertically disposed and hollow filter elements attached to and horizontally spaced across a manifold, with the manifolds connected to a filtrate conduit for removing the hydrocarbon liquid from the slurry.
2. Background of the Disclosure
Slurry hydrocarbon synthesis (HCS) processes are known. In a slurry HCS process a synthesis gas (syngas) comprising a mixture of H2 and CO is bubbled up as a third phase through a slurry in a reactor in which the slurry liquid comprises hydrocarbon products of the synthesis reaction and the dispersed, suspended solids comprise a suitable Fischer-Tropsch type hydrocarbon synthesis catalyst. Reactors which contain such a three phase slurry are sometimes referred to as “bubble columns”, as is disclosed in U.S. Pat. No. 5,348,982. Irrespective of whether the slurry reactor is operated as a dispersed or slumped bed, the mixing conditions in the slurry will typically be somewhere between the two theoretical conditions of plug flow and back mixed. The catalyst particles are typically kept dispersed and suspended in the liquid by the lifting action of the syngas bubbling up through the slurry and by hydraulic means. Mechanical means such as impellers and propellers and the like are not used, because they will quickly erode and also cause attrition of the catalyst particles. One or more vertical, gas disengaging downcomers may be used as hydraulic means to assist in maintaining more uniform catalyst dispersion, by providing a vertical catalyst circulation in the slurry, as is disclosed in U.S. Pat. No. 5,382,748. The slurry liquid comprises the liquid hydrocarbon products of the HCS reaction and must be separated from the catalyst particles and removed from the reactor for further processing and upgrading. This is typically accomplished by mechanical filtration in which the slurry is fed to one or more filters, either inside the slurry in the reactor or outside the reactor, which permit the liquid to pass through, but not the catalyst particles. U.S. Pat. No. 5,527,473 and patent publications EP 0609079, WO 93/16796 and WO 94/16807 all relate to helically wound wedge wire filters and the like, while WO 93/16795 discloses vertical or helically wound fine metal threads or sintered metal. Magnetically assisted filtration has also been disclosed. Notwithstanding the disclosures of the prior art, there is still a need for an efficient and easily replaceable filter which can be immersed in the slurry.